linux-ext4 - [PATCH 1/1] ext4: Remove empty index blocks when punching holes

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Date:	Wed, 29 Feb 2012 00:37:28 -0700
From:	Allison Henderson <achender@...ux.vnet.ibm.com>
To:	linux-ext4@...r.kernel.org
Cc:	Allison Henderson <achender@...ux.vnet.ibm.com>
Subject: [PATCH 1/1] ext4: Remove empty index blocks when punching holes

When punching holes, it is possible that all the entries of an
index block may be removed.  These empty index blocks need to
be removed once punch hole completes.  This patch adds some extra
logic to the punch hole code to remove empty index blocks.

Signed-off-by: Allison Henderson <achender@...ux.vnet.ibm.com>
---
:100644 100644 ad39627... 6bb2f55... M	fs/ext4/extents.c
 fs/ext4/extents.c |   17 ++++++++++++++++-
 1 files changed, 16 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index ad39627..6bb2f55 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3709,7 +3709,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 	struct ext4_extent newex, *ex, *ex2;
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	ext4_fsblk_t newblock = 0;
-	int free_on_err = 0, err = 0, depth, ret;
+	int free_on_err = 0, err = 0, depth, ret, i;
 	unsigned int allocated = 0, offset = 0;
 	unsigned int allocated_clusters = 0, reserved_clusters = 0;
 	unsigned int punched_out = 0;
@@ -3880,6 +3880,21 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 			err = ext4_ext_rm_leaf(handle, inode, path,
 					       &partial_cluster, map->m_lblk,
 					       map->m_lblk + punched_out);
+			if (err)
+				goto out2;
+
+			/*
+			 * Walk back up the path and remove
+			 * empty index blocks
+			 */
+			for (i = depth - 1; i > 0; i--) {
+				if (path[i].p_hdr->eh_entries == 0) {
+					err = ext4_ext_rm_idx(handle, inode,
+								path + i);
+					if (err)
+						goto out2;
+				}
+			}
 
 			if (!err && path->p_hdr->eh_entries == 0) {
 				/*
-- 
1.7.1

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